Ablative liner

Abstract

An improved rocket motor has a first layer of silicone rubber and a second layer of an ablative lining placed between the rocket motor casing and the propellant grain. The ablative lining layer contains chopped novoloid fibers 14 microns in diameter and nominally 1 mm in length interspersed throughout a polymeric composition.

What is claimed is: 
     
       1. An improved end burning rocket motor having reduced propellant grain coning and diminished carcinogenic by-products comprising: a tubular shaped casing having an inner surface,   a silicone rubber layer on said surface;   an ablative lining on said layer made from a mixture of about 74.5 percent by weight polypropylene glycol,   about 1.0 percent by weight N-Mono(hydroxyethyl)-N,N',N'-tris(2-hydroxypropyl)ethylenediamine,   about 10.38 percent by weight toluene-2,4-diisocyanate,   about 0.62 percent by weight N-phenyl-N'-cyclohexyl-p-phenylenediamine,   about 10.0 percent by weight TiO 2 ,   about 2.0 percent by weight novoloid fibers, and   about 1.5 percent by weight ferric acetylacetonate; and      propellant grain bonded to said lining.   
     
     
       2. An improved rocket motor according to claim 1 wherein said fibers are nominal length of 1 mm and diameter of 14 microns. 
     
     
       3. A method of producing a rocket motor having reduced propellant grain coning and diminished carcinogenic by-products comprising: coating the inner surface of a rocket motor casing with a layer of silicone rubber;   applying a mixture of about 74.5 percent by weight polypropylene glycol, about 1.0 percent by weight N-mono(hydroxyethyl)-N,N',N'-tris(2-hydroxypropyl)ethylenediamine, about 10.38 percent by weight toluene-2,4-diisocyanate, about 0.62 percent by weight N-phenyl-N'-cyclohexyl-p-phenylenediamine, about 10.0 percent by weight TiO 2 , and 2.0 percent by weight novoloid fibers; and about 1.5 percent by weight ferric acetylacetonate on said layer; and   pouring a propellant grain in remainder of said casing.   
     
     
       4. A method of producing a rocket motor according to claim 3 wherein said step of applying a mixture includes the sling lining of said mixture. 
     
     
       5. A method of producing a rocket motor according to claim 3 wherein said step of applying a mixture includes the spin lining of said mixture.